In the photographic field, it is well known to use various kinds of polymers or copolymers as a mordant for preventing the transfer of dyes. Polymer mordants are disclosed in, for example, U.S. Pat. Nos. 3,898,088, 3,958,955, 4,131,469, and 4,147,548, West German Patent Application (OLS) No. 2,941,818 and Japanese Patent Application (OPI) No. 17352/81 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application").
It has been found that when photographic prints containing dyes mordanted by the foregoing mordants are exposed to a fluorescent lamp, a mercury lamp or sunlight, the dyes thus mordanted undergo chemical change or decomposition. If the density of the dye images is reduced by the chemical change or decomposition of the dyes, the image quality of the photographic prints becomes very poor and, hence, the development of a technique for preventing the chemical change or decomposition of dyes has been desired.